101
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Bennett PM, Ehler E, Wilson AJ. Sarcoplasmic reticulum is an intermediary of mitochondrial and myofibrillar growth at the intercalated disc. J Muscle Res Cell Motil 2016; 37:55-69. [PMID: 27329158 PMCID: PMC5010836 DOI: 10.1007/s10974-016-9444-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 05/22/2016] [Indexed: 11/30/2022]
Abstract
In cardiomyocytes columns of intermyofibrillar mitochondria run up to the intercalated disc (ID); half are collinear with those in the neighbouring cell, suggesting coordinated addition of sarcomeres and mitochondria both within and between cells during cardiomyocyte growth. Recent evidence for an association between sarcoplasmic reticulum (SR) and mitochondria indicates that the SR may be an intermediary in this coordinated behaviour. For this reason we have investigated the arrangement of SR and t tubules with respect to mitochondria and myofibrils, particularly at the ID. In the body of the cardiomyocyte the mitochondrial columns are frequently intersected by transverse tubules. In addition, we find that a majority of axial tubules are sandwiched between mitochondria and myofibril. No tubules are found at the ID. SR coats mitochondrial columns and fibrils throughout their length and reaches towards the peaks of the ID membrane where it attaches in the form of junctional (j)SR. These peripheral ID couplings are often situated between mitochondria and ID membrane, suggesting an SR connection between the two. In dilated cardiomyopathy (DCM) the mitochondria are somewhat disordered and clumped. In a mouse model for DCM, the muscle LIM protein KO, we find that there is a lack of mitochondria near the ID, suggesting the uncoupling of the myofibril/mitochondria organisation during growth. SR still coats the fibrils and reaches the ID folds in a jSR coupling. Unlike in control tissue, however, loops and long fingers of ID membrane penetrate into the proximal sarcomere suggesting a possible intermediary state in cardiomyocyte growth.
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Affiliation(s)
- Pauline M Bennett
- Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London, SE1 1UL, UK.
| | - Elisabeth Ehler
- Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London, SE1 1UL, UK
| | - Amanda J Wilson
- Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London, SE1 1UL, UK.,Department of Life Sciences, Sir Ernst Chain Building, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK
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102
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Bang ML. Animal Models of Congenital Cardiomyopathies Associated With Mutations in Z-Line Proteins. J Cell Physiol 2016; 232:38-52. [PMID: 27171814 DOI: 10.1002/jcp.25424] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 05/10/2016] [Indexed: 01/15/2023]
Abstract
The cardiac Z-line at the boundary between sarcomeres is a multiprotein complex connecting the contractile apparatus with the cytoskeleton and the extracellular matrix. The Z-line is important for efficient force generation and transmission as well as the maintenance of structural stability and integrity. Furthermore, it is a nodal point for intracellular signaling, in particular mechanosensing and mechanotransduction. Mutations in various genes encoding Z-line proteins have been associated with different cardiomyopathies, including dilated cardiomyopathy, hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, restrictive cardiomyopathy, and left ventricular noncompaction, and mutations even within the same gene can cause widely different pathologies. Animal models have contributed to a great advancement in the understanding of the physiological function of Z-line proteins and the pathways leading from mutations in Z-line proteins to cardiomyopathy, although genotype-phenotype prediction remains a great challenge. This review presents an overview of the currently available animal models for Z-line and Z-line associated proteins involved in human cardiomyopathies with special emphasis on knock-in and transgenic mouse models recapitulating the clinical phenotypes of human cardiomyopathy patients carrying mutations in Z-line proteins. Pros and cons of mouse models will be discussed and a future outlook will be given. J. Cell. Physiol. 232: 38-52, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Marie-Louise Bang
- Institute of Genetic and Biomedical Research, UOS Milan, National Research Council and Humanitas Clinical and Research Center, Rozzano, Milan, Italy.
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103
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Hille S, Dierck F, Kühl C, Sosna J, Adam-Klages S, Adam D, Lüllmann-Rauch R, Frey N, Kuhn C. Dyrk1a regulates the cardiomyocyte cell cycle via D-cyclin-dependent Rb/E2f-signalling. Cardiovasc Res 2016; 110:381-94. [PMID: 27056896 DOI: 10.1093/cvr/cvw074] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 04/01/2016] [Indexed: 11/14/2022] Open
Abstract
AIMS Down syndrome-associated dual-specificity tyrosine-(Y)-phosphorylation-regulated kinase 1A (DYRK1A) is a ubiquitously expressed protein kinase. Up to date a variety of targets have been identified, establishing a key role for Dyrk1a in selected signalling pathways. In cardiomyocytes, Dyrk1a acts as a negative regulator of hypertrophy by phosphorylating transcription factors of the NFAT family, but its mechanistic function in the heart remains poorly understood. This study was designed to investigate a potential protective role of Dyrk1a in cardiac hypertrophy in vivo. METHODS AND RESULTS We generated transgenic mice with cardiac-specific overexpression of Dyrk1a. Counterintuitively, these mice developed severe dilated cardiomyopathy associated with congestive heart failure and premature death. In search for the cause of this unexpected phenotype, we found that Dyrk1a interacts with all members of the D-cyclin family and represses their protein levels in vitro and in vivo. Particularly, forced expression of Dyrk1a leads to increased phosphorylation of Ccnd2 on Thr280 and promotes its subsequent proteasomal degradation. Accordingly, cardiomyocytes overexpressing Dyrk1a display hypo-phosphorylated Rb1, suppression of Rb/E2f-signalling, and reduced expression of E2f-target genes, which ultimately results in impaired cell cycle progression. CONCLUSIONS We identified Dyrk1a as a novel negative regulator of D-cyclin-mediated Rb/E2f-signalling. As dysregulation of this pathway with impaired cardiomyocyte proliferation leads to cardiomyopathy, dose-specific Dyrk1a expression and activity appears to be critical for the hyperplastic and hypertrophic growth of the developing heart.
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MESH Headings
- Animals
- Cardiomegaly/enzymology
- Cardiomegaly/genetics
- Cardiomegaly/pathology
- Cardiomegaly/physiopathology
- Cardiomyopathy, Dilated/enzymology
- Cardiomyopathy, Dilated/genetics
- Cardiomyopathy, Dilated/pathology
- Cardiomyopathy, Dilated/physiopathology
- Cell Cycle
- Cell Proliferation
- Cyclin D/genetics
- Cyclin D/metabolism
- Disease Models, Animal
- E2F Transcription Factors/metabolism
- Gene Expression Regulation
- HEK293 Cells
- Heart Failure/enzymology
- Heart Failure/genetics
- Heart Failure/pathology
- Heart Failure/physiopathology
- Humans
- Mice, Inbred C57BL
- Mice, Transgenic
- Myocytes, Cardiac/enzymology
- Myocytes, Cardiac/pathology
- Phosphorylation
- Protein Binding
- Protein Serine-Threonine Kinases/genetics
- Protein Serine-Threonine Kinases/metabolism
- Protein-Tyrosine Kinases/genetics
- Protein-Tyrosine Kinases/metabolism
- Rats, Wistar
- Retinoblastoma/metabolism
- Signal Transduction
- Time Factors
- Transfection
- Dyrk Kinases
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Affiliation(s)
- Susanne Hille
- Department of Internal Medicine III, University Medical Center of Schleswig-Holstein, Campus Kiel, Arnold-Heller-Str. 3 (Building 6), 24105 Kiel, Germany DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Kiel, Germany
| | - Franziska Dierck
- Department of Internal Medicine III, University Medical Center of Schleswig-Holstein, Campus Kiel, Arnold-Heller-Str. 3 (Building 6), 24105 Kiel, Germany DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Kiel, Germany
| | - Constantin Kühl
- Department of Internal Medicine III, University Medical Center of Schleswig-Holstein, Campus Kiel, Arnold-Heller-Str. 3 (Building 6), 24105 Kiel, Germany DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Kiel, Germany
| | - Justyna Sosna
- Institute of Immunology, Christian-Albrechts-University Kiel, UKSH Campus Kiel, 24105 Kiel, Germany
| | - Sabine Adam-Klages
- Institute of Immunology, Christian-Albrechts-University Kiel, UKSH Campus Kiel, 24105 Kiel, Germany
| | - Dieter Adam
- Institute of Immunology, Christian-Albrechts-University Kiel, UKSH Campus Kiel, 24105 Kiel, Germany
| | | | - Norbert Frey
- Department of Internal Medicine III, University Medical Center of Schleswig-Holstein, Campus Kiel, Arnold-Heller-Str. 3 (Building 6), 24105 Kiel, Germany DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Kiel, Germany
| | - Christian Kuhn
- Department of Internal Medicine III, University Medical Center of Schleswig-Holstein, Campus Kiel, Arnold-Heller-Str. 3 (Building 6), 24105 Kiel, Germany DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Kiel, Germany
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104
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Broughton KM, Li J, Sarmah E, Warren CM, Lin YH, Henze MP, Sanchez-Freire V, Solaro RJ, Russell B. A myosin activator improves actin assembly and sarcomere function of human-induced pluripotent stem cell-derived cardiomyocytes with a troponin T point mutation. Am J Physiol Heart Circ Physiol 2016; 311:H107-17. [PMID: 27199119 DOI: 10.1152/ajpheart.00162.2016] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 05/02/2016] [Indexed: 11/22/2022]
Abstract
We have investigated cardiac myocytes derived from human-induced pluripotent stem cells (iPSC-CMs) from two normal control and two family members expressing a mutant cardiac troponin T (cTnT-R173W) linked to dilated cardiomyopathy (DCM). cTnT is a regulatory protein of the sarcomeric thin filament. The loss of this basic charge, which is strategically located to control tension, has consequences leading to progressive DCM. iPSC-CMs serve as a valuable platform for understanding clinically relevant mutations in sarcomeric proteins; however, there are important questions to be addressed with regard to myocyte adaptation that we model here by plating iPSC-CMs on softer substrates (100 kPa) to create a more physiologic environment during recovery and maturation of iPSC-CMs after thawing from cryopreservation. During the first week of culture of the iPSC-CMs, we have determined structural and functional characteristics as well as actin assembly dynamics. Shortening, actin content, and actin assembly dynamics were depressed in CMs from the severely affected mutant at 1 wk of culture, but by 2 wk differences were less apparent. Sarcomeric troponin and myosin isoform composition were fetal/neonatal. Furthermore, the troponin complex, reconstituted with wild-type cTnT or recombinant cTnT-R173W, depressed the entry of cross-bridges into the force-generating state, which can be reversed by the myosin activator omecamtiv mecarbil. Therapeutic doses of this drug increased both contractility and the content of F-actin in the mutant iPSC-CMs. Collectively, our data suggest the use of a myosin activation reagent to restore function within patient-specific iPSC-CMs may aid in understanding and treating this familial DCM.
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Affiliation(s)
- K M Broughton
- Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois
| | - J Li
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois; and
| | - E Sarmah
- Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois
| | - C M Warren
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois; and
| | - Y-H Lin
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois; and
| | - M P Henze
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois; and
| | - V Sanchez-Freire
- Department of Medicine, Division of Cardiology, Stanford University School of Medicine, Stanford, California
| | - R J Solaro
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois; and
| | - B Russell
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois; and
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105
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Smart N, Hill AA, Cross JC, Riley PR. A differential screen for putative targets of the bHLH transcription factor Hand1 in cardiac morphogenesis. Mech Dev 2016; 119 Suppl 1:S65-71. [PMID: 14516662 DOI: 10.1016/s0925-4773(03)00093-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The bHLH transcription factor, Hand1 has been implicated in cardiac looping in the mouse, however its function in the developing heart remains unknown. To investigate the mechanism(s) through which Hand1 might function, we screened for potential downstream target genes using representational difference analysis. Thymosin beta4 was found to be down-regulated whereas cystatin C and alphaCA were up-regulated in Hand1-null embryoid bodies. Whole-mount in situ hybridisation on wild type embryos (E8.0-E10.5) and Hand1 homozygous-mutant embryos (E8.0) confirmed co-expression of the putative targets with Hand1 in the heart and their aberrant expression in a Hand1-null background.
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Affiliation(s)
- Nicola Smart
- Molecular Medicine Unit, Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK
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106
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Molecular cloning, characterization and tissue specificity of the expression of the ovine CSRP2 and CSRP3 genes from Small-tail Han sheep (Ovis aries). Gene 2016; 580:47-57. [DOI: 10.1016/j.gene.2016.01.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 12/22/2015] [Accepted: 01/04/2016] [Indexed: 11/19/2022]
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107
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Liang Y, Sheikh F. Scaffold Proteins Regulating Extracellular Regulated Kinase Function in Cardiac Hypertrophy and Disease. Front Pharmacol 2016; 7:37. [PMID: 26973524 PMCID: PMC4770026 DOI: 10.3389/fphar.2016.00037] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Accepted: 02/11/2016] [Indexed: 01/07/2023] Open
Abstract
The mitogen activated protein kinase (MAPK)-extracellular regulated kinase 1/2 (ERK1/2) pathway is a central downstream signaling pathway that is activated in cardiac muscle cells during mechanical and agonist-mediated hypertrophy. Studies in genetic mouse models deficient in ERK-associated MAPK components pathway have further reinforced a direct role for this pathway in stress-induced cardiac hypertrophy and disease. However, more recent studies have highlighted that these signaling pathways may exert their regulatory functions in a more compartmentalized manner in cardiac muscle. Emerging data has uncovered specific MAPK scaffolding proteins that tether MAPK/ERK signaling specifically at the sarcomere and plasma membrane in cardiac muscle and show that deficiencies in these scaffolding proteins alter ERK activity and phosphorylation, which are then critical in altering the cardiac myocyte response to stress-induced hypertrophy and disease progression. In this review, we provide insights on ERK-associated scaffolding proteins regulating cardiac myofilament function and their impact on cardiac hypertrophy and disease.
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Affiliation(s)
- Yan Liang
- Department of Medicine, University of California-San Diego, La Jolla CA, USA
| | - Farah Sheikh
- Department of Medicine, University of California-San Diego, La Jolla CA, USA
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108
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Abstract
Background Genome-wide mapping reveals chromatin landscapes unique to cell states. Histone marks of regulatory genes involved in cell specification and organ development provide a powerful tool to map regulatory sequences. H3K4me3 marks promoter regions; H3K27me3 marks repressed regions, and Pol II presence indicates active transcription. The presence of both H3K4me3 and H3K27me3 characterize poised sequences, a common characteristic of genes involved in pattern formation during organogenesis. Results We used genome-wide profiling for H3K27me3, H3K4me3, and Pol II to map chromatin states in mouse embryonic day 12 forelimbs in wild type (control) and Pitx2-null mutant mice. We compared these data with previous gene expression studies from forelimb Lbx1+ migratory myoblasts and correlated Pitx2-dependent expression profiles and chromatin states. During forelimb development, several lineages including myoblast, osteoblast, neurons, angioblasts etc., require synchronized growth to form a functional limb. We identified 125 genes in the developing forelimb that are Pitx2-dependent. Genes involved in muscle specification and cytoskeleton architecture were positively regulated, while genes involved in axonal path finding were poised. Conclusion Our results have established histone modification profiles as a useful tool for identifying gene regulatory states in muscle development, and identified the role of Pitx2 in extending the time of myoblast progression, promoting formation of sarcomeric structures, and suppressing attachment of neuronal axons.
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Affiliation(s)
- Arun J Singh
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, OR 97331, USA
| | - Michael K Gross
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, OR 97331, USA
| | - Theresa M Filtz
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, OR 97331, USA
| | - Chrissa Kioussi
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, OR 97331, USA
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109
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Field J, Ye DZ, Shinde M, Liu F, Schillinger KJ, Lu M, Wang T, Skettini M, Xiong Y, Brice AK, Chung DC, Patel VV. CAP2 in cardiac conduction, sudden cardiac death and eye development. Sci Rep 2015; 5:17256. [PMID: 26616005 PMCID: PMC4663486 DOI: 10.1038/srep17256] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 10/14/2015] [Indexed: 02/03/2023] Open
Abstract
Sudden cardiac death kills 180,000 to 450,000 Americans annually, predominantly males. A locus that confers a risk for sudden cardiac death, cardiac conduction disease, and a newly described developmental disorder (6p22 syndrome) is located at 6p22. One gene at 6p22 is CAP2, which encodes a cytoskeletal protein that regulates actin dynamics. To determine the role of CAP2 in vivo, we generated knockout (KO) mice. cap2−/cap2− males were underrepresented at weaning and ~70% died by 12 weeks of age, but cap2−/cap2− females survived at close to the expected levels and lived normal life spans. CAP2 knockouts resembled patients with 6p22 syndrome in that mice were smaller and they developed microphthalmia and cardiac disease. The cardiac disease included cardiac conduction disease (CCD) and, after six months of age, dilated cardiomyopathy (DCM), most noticeably in the males. To address the mechanisms underlying these phenotypes, we used Cre-mediated recombination to knock out CAP2 in cardiomyocytes. We found that the mice developed CCD, leading to sudden cardiac death from complete heart block, but no longer developed DCM or the other phenotypes, including sex bias. These studies establish a direct role for CAP2 and actin dynamics in sudden cardiac death and cardiac conduction disease.
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Affiliation(s)
- Jeffrey Field
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine Philadelphia, Pennsylvania 19041 USA
| | - Diana Z Ye
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine Philadelphia, Pennsylvania 19041 USA
| | - Manasi Shinde
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine Philadelphia, Pennsylvania 19041 USA
| | - Fang Liu
- Cardiovascular Institute, University of Pennsylvania Perelman School of Medicine Philadelphia, Pennsylvania 19041 USA
| | - Kurt J Schillinger
- Cardiovascular Institute, University of Pennsylvania Perelman School of Medicine Philadelphia, Pennsylvania 19041 USA.,Section of Cardiac Electrophysiology, University of Pennsylvania Perelman School of Medicine Philadelphia, Pennsylvania 19041 USA
| | - MinMin Lu
- Cardiovascular Institute, University of Pennsylvania Perelman School of Medicine Philadelphia, Pennsylvania 19041 USA
| | - Tao Wang
- Cardiovascular Institute, University of Pennsylvania Perelman School of Medicine Philadelphia, Pennsylvania 19041 USA
| | - Michelle Skettini
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine Philadelphia, Pennsylvania 19041 USA
| | - Yao Xiong
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine Philadelphia, Pennsylvania 19041 USA
| | - Angela K Brice
- University Laboratory Animal Resources and School of Veterinary Medicine, Department of Pathobiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Daniel C Chung
- Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Pennsylvania 19041 USA
| | - Vickas V Patel
- Cardiovascular Institute, University of Pennsylvania Perelman School of Medicine Philadelphia, Pennsylvania 19041 USA.,Section of Cardiac Electrophysiology, University of Pennsylvania Perelman School of Medicine Philadelphia, Pennsylvania 19041 USA
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110
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Brody MJ, Feng L, Grimes AC, Hacker TA, Olson TM, Kamp TJ, Balijepalli RC, Lee Y. LRRC10 is required to maintain cardiac function in response to pressure overload. Am J Physiol Heart Circ Physiol 2015; 310:H269-78. [PMID: 26608339 DOI: 10.1152/ajpheart.00717.2014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 11/18/2015] [Indexed: 01/08/2023]
Abstract
We previously reported that the cardiomyocyte-specific leucine-rich repeat containing protein (LRRC)10 has critical functions in the mammalian heart. In the present study, we tested the role of LRRC10 in the response of the heart to biomechanical stress by performing transverse aortic constriction on Lrrc10-null (Lrrc10(-/-)) mice. Mild pressure overload induced severe cardiac dysfunction and ventricular dilation in Lrrc10(-/-) mice compared with control mice. In addition to dilation and cardiomyopathy, Lrrc10(-/-) mice showed a pronounced increase in heart weight with pressure overload stimulation and a more dramatic loss of cardiac ventricular performance, collectively suggesting that the absence of LRRC10 renders the heart more disease prone with greater hypertrophy and structural remodeling, although rates of cardiac fibrosis and myocyte dropout were not different from control mice. Lrrc10(-/-) cardiomyocytes also exhibited reduced contractility in response to β-adrenergic stimulation, consistent with loss of cardiac ventricular performance after pressure overload. We have previously shown that LRRC10 interacts with actin in the heart. Here, we show that His(150) of LRRC10 was required for an interaction with actin, and this interaction was reduced after pressure overload, suggesting an integral role for LRRC10 in the response of the heart to mechanical stress. Importantly, these experiments demonstrated that LRRC10 is required to maintain cardiac performance in response to pressure overload and suggest that dysregulated expression or mutation of LRRC10 may greatly sensitize human patients to more severe cardiac disease in conditions such as chronic hypertension or aortic stenosis.
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Affiliation(s)
- Matthew J Brody
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin; Molecular and Environmental Toxicology Center, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| | - Li Feng
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin; and
| | - Adrian C Grimes
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin; and
| | - Timothy A Hacker
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin; and
| | - Timothy M Olson
- Cardiovascular Genetics Research Laboratory and Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota
| | - Timothy J Kamp
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin; Department of Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin; and
| | - Ravi C Balijepalli
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin; and
| | - Youngsook Lee
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin; Molecular and Environmental Toxicology Center, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin;
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111
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Knockout of Lmod2 results in shorter thin filaments followed by dilated cardiomyopathy and juvenile lethality. Proc Natl Acad Sci U S A 2015; 112:13573-8. [PMID: 26487682 DOI: 10.1073/pnas.1508273112] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Leiomodin 2 (Lmod2) is an actin-binding protein that has been implicated in the regulation of striated muscle thin filament assembly; its physiological function has yet to be studied. We found that knockout of Lmod2 in mice results in abnormally short thin filaments in the heart. We also discovered that Lmod2 functions to elongate thin filaments by promoting actin assembly and dynamics at thin filament pointed ends. Lmod2-KO mice die as juveniles with hearts displaying contractile dysfunction and ventricular chamber enlargement consistent with dilated cardiomyopathy. Lmod2-null cardiomyocytes produce less contractile force than wild type when plated on micropillar arrays. Introduction of GFP-Lmod2 via adeno-associated viral transduction elongates thin filaments and rescues structural and functional defects observed in Lmod2-KO mice, extending their lifespan to adulthood. Thus, to our knowledge, Lmod2 is the first identified mammalian protein that functions to elongate actin filaments in the heart; it is essential for cardiac thin filaments to reach a mature length and is required for efficient contractile force and proper heart function during development.
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112
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QU XINKAI, YUAN FANG, LI RUOGU, XU LEI, JING WEIFENG, LIU HUA, XU YINGJIA, ZHANG MIN, LIU XU, FANG WEIYI, YANG YIQING, QIU XINGBIAO. Prevalence and spectrum of LRRC10 mutations associated with idiopathic dilated cardiomyopathy. Mol Med Rep 2015; 12:3718-3724. [DOI: 10.3892/mmr.2015.3843] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 05/01/2015] [Indexed: 11/06/2022] Open
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113
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Tumor necrosis factor-α confers cardioprotection through ectopic expression of keratins K8 and K18. Nat Med 2015; 21:1076-84. [PMID: 26280121 DOI: 10.1038/nm.3925] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 07/15/2015] [Indexed: 12/18/2022]
Abstract
Tumor necrosis factor-α (TNF-α), one of the major stress-induced proinflammatory cytokines, is upregulated in the heart after tissue injury, and its sustained expression can contribute to the development of heart failure. Whether TNF-α also exerts cytoprotective effects in heart failure is not known. Here we provide evidence for a cardioprotective function of TNF-α in a genetic heart failure model, desmin-deficient mice. The cardioprotective effects of TNF-α are a consequence of nuclear factor-κB (NF-κB)-mediated ectopic expression in cardiomyocytes of keratin 8 (K8) and keratin 18 (K18), two epithelial-specific intermediate filament proteins. In cardiomyocytes, K8 and K18 (K8/K18) formed an alternative cytoskeletal network that localized mainly at intercalated discs (IDs) and conferred cardioprotection by maintaining normal ID structure and mitochondrial integrity and function. Ectopic induction of K8/K18 expression in cardiomyocytes also occurred in other genetic and experimental models of heart failure. Loss of the K8/K18 network resulted in a maladaptive cardiac phenotype following transverse aortic constriction. In human failing myocardium, where TNF-α expression is upregulated, K8/K18 were also ectopically expressed and localized primarily at IDs, which did not contain detectable amounts of desmin. Thus, TNF-α- and NF-κB-mediated formation of an alternative, stress-induced intermediate filament cytoskeleton has cardioprotective function in mice and potentially in humans.
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114
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Rashid MM, Runci A, Polletta L, Carnevale I, Morgante E, Foglio E, Arcangeli T, Sansone L, Russo MA, Tafani M. Muscle LIM protein/CSRP3: a mechanosensor with a role in autophagy. Cell Death Discov 2015; 1:15014. [PMID: 27551448 PMCID: PMC4981024 DOI: 10.1038/cddiscovery.2015.14] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 06/11/2015] [Accepted: 06/12/2015] [Indexed: 12/12/2022] Open
Abstract
Muscle LIM protein (MLP) is a microtubule-associated protein expressed in cardiac and muscle tissues that belongs to the cysteine-rich protein (CSRP/CRP) family. MLP has a central role during muscle development and for architectural maintenance of muscle cells. However, muscle cells rely on autophagy during differentiation and for structural maintenance. To study the role of MLP in autophagy, we have used C2C12 mouse myoblasts silenced or overexpressing MLP. Our results show that MLP contributes to the correct autophagosome formation and flux by interacting with LC3 as demonstrated by co-immunoprecipitation and PLA assay. In fact, MLP silencing results in decreased LC3-II staining and absent degradation of long-lived proteins. Moreover, MLP silencing impaired myoblasts differentiation as measured by decreased expression of MyoD1, MyoG1 and myosin heavy chain. Ultrastructural analysis revealed the presence of large empty autophagosomes in myoblasts and multimembranous structures in myotubes from MLP-silenced clones. Impaired autophagy in MLP-silenced cells resulted in increased susceptibility to apoptotic cell death. In fact, treatment of MLP-silenced C2C12 myoblasts and myotubes with staurosporine resulted in increased caspase-3 and PARP cleavage as well as increased percentage of cell death. In conclusion, we propose that MLP regulates autophagy during muscle cell differentiation or maintenance through a mechanism involving MLP/LC3-II interaction and correct autophagosome formation.
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Affiliation(s)
- M M Rashid
- Department of Experimental Medicine, University of Rome , Sapienza, Rome, Italy
| | - A Runci
- Department of Experimental Medicine, University of Rome , Sapienza, Rome, Italy
| | - L Polletta
- Department of Experimental Medicine, University of Rome , Sapienza, Rome, Italy
| | - I Carnevale
- Department of Experimental Medicine, University of Rome , Sapienza, Rome, Italy
| | - E Morgante
- Department of Experimental Medicine, University of Rome , Sapienza, Rome, Italy
| | - E Foglio
- Department of Experimental Medicine, University of Rome , Sapienza, Rome, Italy
| | - T Arcangeli
- Department of Experimental Medicine, University of Rome , Sapienza, Rome, Italy
| | - L Sansone
- Department of Cellular and Molecular Pathology, IRCCS San Raffaele , Rome, Italy
| | - M A Russo
- Consorzio MEBIC, San Raffaele University , Rome, Italy
| | - M Tafani
- Department of Experimental Medicine, University of Rome, Sapienza, Rome, Italy; Department of Cellular and Molecular Pathology, IRCCS San Raffaele, Rome, Italy
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115
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Vafiadaki E, Arvanitis DA, Sanoudou D. Muscle LIM Protein: Master regulator of cardiac and skeletal muscle functions. Gene 2015; 566:1-7. [PMID: 25936993 PMCID: PMC6660132 DOI: 10.1016/j.gene.2015.04.077] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 04/21/2015] [Accepted: 04/27/2015] [Indexed: 12/17/2022]
Abstract
Muscle LIM Protein (MLP) has emerged as a key regulator of striated muscle physiology and pathophysiology. Mutations in cysteine and glycine-rich protein 3 (CSRP3), the gene encoding MLP, are causative of human cardiomyopathies, whereas altered expression patterns are observed in human failing heart and skeletal myopathies. In vitro and in vivo evidences reveal a complex and diverse functional role of MLP in striated muscle, which is determined by its multiple interacting partners and subcellular distribution. Experimental evidence suggests that MLP is implicated in both myogenic differentiation and myocyte cytoarchitecture, although the full spectrum of its intracellular roles still unfolds.
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Affiliation(s)
- Elizabeth Vafiadaki
- Molecular Biology Division, Biomedical Research Foundation of the Academy of Athens, Greece
| | - Demetrios A Arvanitis
- Molecular Biology Division, Biomedical Research Foundation of the Academy of Athens, Greece
| | - Despina Sanoudou
- Molecular Biology Division, Biomedical Research Foundation of the Academy of Athens, Greece; 4th Department of Internal Medicine, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, Greece.
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Buyandelger B, Mansfield C, Kostin S, Choi O, Roberts AM, Ware JS, Mazzarotto F, Pesce F, Buchan R, Isaacson RL, Vouffo J, Gunkel S, Knöll G, McSweeney SJ, Wei H, Perrot A, Pfeiffer C, Toliat MR, Ilieva K, Krysztofinska E, López-Olañeta MM, Gómez-Salinero JM, Schmidt A, Ng KE, Teucher N, Chen J, Teichmann M, Eilers M, Haverkamp W, Regitz-Zagrosek V, Hasenfuss G, Braun T, Pennell DJ, Gould I, Barton PJR, Lara-Pezzi E, Schäfer S, Hübner N, Felkin LE, O'Regan DP, Brand T, Milting H, Nürnberg P, Schneider MD, Prasad S, Petretto E, Knöll R. ZBTB17 (MIZ1) Is Important for the Cardiac Stress Response and a Novel Candidate Gene for Cardiomyopathy and Heart Failure. ACTA ACUST UNITED AC 2015; 8:643-52. [PMID: 26175529 DOI: 10.1161/circgenetics.113.000690] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 07/02/2015] [Indexed: 12/30/2022]
Abstract
BACKGROUND Mutations in sarcomeric and cytoskeletal proteins are a major cause of hereditary cardiomyopathies, but our knowledge remains incomplete as to how the genetic defects execute their effects. METHODS AND RESULTS We used cysteine and glycine-rich protein 3, a known cardiomyopathy gene, in a yeast 2-hybrid screen and identified zinc-finger and BTB domain-containing protein 17 (ZBTB17) as a novel interacting partner. ZBTB17 is a transcription factor that contains the peak association signal (rs10927875) at the replicated 1p36 cardiomyopathy locus. ZBTB17 expression protected cardiac myocytes from apoptosis in vitro and in a mouse model with cardiac myocyte-specific deletion of Zbtb17, which develops cardiomyopathy and fibrosis after biomechanical stress. ZBTB17 also regulated cardiac myocyte hypertrophy in vitro and in vivo in a calcineurin-dependent manner. CONCLUSIONS We revealed new functions for ZBTB17 in the heart, a transcription factor that may play a role as a novel cardiomyopathy gene.
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Du Bois P, Pablo Tortola C, Lodka D, Kny M, Schmidt F, Song K, Schmidt S, Bassel-Duby R, Olson EN, Fielitz J. Angiotensin II Induces Skeletal Muscle Atrophy by Activating TFEB-Mediated MuRF1 Expression. Circ Res 2015; 117:424-36. [PMID: 26137861 DOI: 10.1161/circresaha.114.305393] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2014] [Accepted: 07/02/2015] [Indexed: 11/16/2022]
Abstract
RATIONALE Skeletal muscle wasting with accompanying cachexia is a life threatening complication in congestive heart failure. The molecular mechanisms are imperfectly understood, although an activated renin-angiotensin aldosterone system has been implicated. Angiotensin (Ang) II induces skeletal muscle atrophy in part by increased muscle-enriched E3 ubiquitin ligase muscle RING-finger-1 (MuRF1) expression, which may involve protein kinase D1 (PKD1). OBJECTIVE To elucidate the molecular mechanism of Ang II-induced skeletal muscle wasting. METHODS AND RESULTS A cDNA expression screen identified the lysosomal hydrolase-coordinating transcription factor EB (TFEB) as novel regulator of the human MuRF1 promoter. TFEB played a key role in regulating Ang II-induced skeletal muscle atrophy by transcriptional control of MuRF1 via conserved E-box elements. Inhibiting TFEB with small interfering RNA prevented Ang II-induced MuRF1 expression and atrophy. The histone deacetylase-5 (HDAC5), which was directly bound to and colocalized with TFEB, inhibited TFEB-induced MuRF1 expression. The inhibition of TFEB by HDAC5 was reversed by PKD1, which was associated with HDAC5 and mediated its nuclear export. Mice lacking PKD1 in skeletal myocytes were resistant to Ang II-induced muscle wasting. CONCLUSION We propose that elevated Ang II serum concentrations, as occur in patients with congestive heart failure, could activate the PKD1/HDAC5/TFEB/MuRF1 pathway to induce skeletal muscle wasting.
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Affiliation(s)
- Philipp Du Bois
- From the Department of Molecular Cardiology, Experimental and Clinical Research Center (ECRC), a Cooperation between Max-Delbrück-Centrum and Charité Universitätsmedizin Berlin, Campus Buch, Berlin, Germany (P.D.B., C.P.T., D.L., M.K., F.S., S.S., J.F.); Department of Cardiology, Charité Universitätsmedizin Berlin, Campus Virchow, Berlin, Germany (J.F.); and Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas (K.S., R.B.-D., E.N.O.)
| | - Cristina Pablo Tortola
- From the Department of Molecular Cardiology, Experimental and Clinical Research Center (ECRC), a Cooperation between Max-Delbrück-Centrum and Charité Universitätsmedizin Berlin, Campus Buch, Berlin, Germany (P.D.B., C.P.T., D.L., M.K., F.S., S.S., J.F.); Department of Cardiology, Charité Universitätsmedizin Berlin, Campus Virchow, Berlin, Germany (J.F.); and Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas (K.S., R.B.-D., E.N.O.)
| | - Doerte Lodka
- From the Department of Molecular Cardiology, Experimental and Clinical Research Center (ECRC), a Cooperation between Max-Delbrück-Centrum and Charité Universitätsmedizin Berlin, Campus Buch, Berlin, Germany (P.D.B., C.P.T., D.L., M.K., F.S., S.S., J.F.); Department of Cardiology, Charité Universitätsmedizin Berlin, Campus Virchow, Berlin, Germany (J.F.); and Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas (K.S., R.B.-D., E.N.O.)
| | - Melanie Kny
- From the Department of Molecular Cardiology, Experimental and Clinical Research Center (ECRC), a Cooperation between Max-Delbrück-Centrum and Charité Universitätsmedizin Berlin, Campus Buch, Berlin, Germany (P.D.B., C.P.T., D.L., M.K., F.S., S.S., J.F.); Department of Cardiology, Charité Universitätsmedizin Berlin, Campus Virchow, Berlin, Germany (J.F.); and Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas (K.S., R.B.-D., E.N.O.)
| | - Franziska Schmidt
- From the Department of Molecular Cardiology, Experimental and Clinical Research Center (ECRC), a Cooperation between Max-Delbrück-Centrum and Charité Universitätsmedizin Berlin, Campus Buch, Berlin, Germany (P.D.B., C.P.T., D.L., M.K., F.S., S.S., J.F.); Department of Cardiology, Charité Universitätsmedizin Berlin, Campus Virchow, Berlin, Germany (J.F.); and Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas (K.S., R.B.-D., E.N.O.)
| | - Kunhua Song
- From the Department of Molecular Cardiology, Experimental and Clinical Research Center (ECRC), a Cooperation between Max-Delbrück-Centrum and Charité Universitätsmedizin Berlin, Campus Buch, Berlin, Germany (P.D.B., C.P.T., D.L., M.K., F.S., S.S., J.F.); Department of Cardiology, Charité Universitätsmedizin Berlin, Campus Virchow, Berlin, Germany (J.F.); and Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas (K.S., R.B.-D., E.N.O.)
| | - Sibylle Schmidt
- From the Department of Molecular Cardiology, Experimental and Clinical Research Center (ECRC), a Cooperation between Max-Delbrück-Centrum and Charité Universitätsmedizin Berlin, Campus Buch, Berlin, Germany (P.D.B., C.P.T., D.L., M.K., F.S., S.S., J.F.); Department of Cardiology, Charité Universitätsmedizin Berlin, Campus Virchow, Berlin, Germany (J.F.); and Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas (K.S., R.B.-D., E.N.O.)
| | - Rhonda Bassel-Duby
- From the Department of Molecular Cardiology, Experimental and Clinical Research Center (ECRC), a Cooperation between Max-Delbrück-Centrum and Charité Universitätsmedizin Berlin, Campus Buch, Berlin, Germany (P.D.B., C.P.T., D.L., M.K., F.S., S.S., J.F.); Department of Cardiology, Charité Universitätsmedizin Berlin, Campus Virchow, Berlin, Germany (J.F.); and Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas (K.S., R.B.-D., E.N.O.)
| | - Eric N Olson
- From the Department of Molecular Cardiology, Experimental and Clinical Research Center (ECRC), a Cooperation between Max-Delbrück-Centrum and Charité Universitätsmedizin Berlin, Campus Buch, Berlin, Germany (P.D.B., C.P.T., D.L., M.K., F.S., S.S., J.F.); Department of Cardiology, Charité Universitätsmedizin Berlin, Campus Virchow, Berlin, Germany (J.F.); and Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas (K.S., R.B.-D., E.N.O.)
| | - Jens Fielitz
- From the Department of Molecular Cardiology, Experimental and Clinical Research Center (ECRC), a Cooperation between Max-Delbrück-Centrum and Charité Universitätsmedizin Berlin, Campus Buch, Berlin, Germany (P.D.B., C.P.T., D.L., M.K., F.S., S.S., J.F.); Department of Cardiology, Charité Universitätsmedizin Berlin, Campus Virchow, Berlin, Germany (J.F.); and Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas (K.S., R.B.-D., E.N.O.).
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Kötter S, Andresen C, Krüger M. Titin: central player of hypertrophic signaling and sarcomeric protein quality control. Biol Chem 2015; 395:1341-52. [PMID: 25205716 DOI: 10.1515/hsz-2014-0178] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2014] [Accepted: 04/23/2014] [Indexed: 11/15/2022]
Abstract
The giant sarcomeric protein titin has multiple important functions in striated muscle cells. Due to its gigantic size, its central position in the sarcomere and its elastic I-band domains, titin is a scaffold protein that is important for sarcomere assembly, and serves as a molecular spring that defines myofilament distensibility. This review focuses on the emerging role of titin in mechanosensing and hypertrophic signaling, and further highlights recent evidence that links titin to sarcomeric protein turnover.
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119
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Michaelides M, Georgiadou S, Constantinides C. In vivo epicardial force and strain characterisation in normal and MLP-knockout murine hearts. Physiol Meas 2015; 36:1573-90. [PMID: 26057415 DOI: 10.1088/0967-3334/36/7/1573] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The study's objective is to quantify in vivo epicardial force and strain in the normal and transgenic myocardium using microsensors.Male mice (n = 39), including C57BL/6 (n = 26), 129/Sv (n = 5), wild-type (WT) C57 × 129Sv (n = 5), and muscle LIM protein (MLP) knock-out (n = 3), were studied under 1.5% isoflurane anaesthesia. Microsurgery allowed the placement of two piezoelectric crystals at longitudinal epicardial loci at the basal, middle, and apical LV regions, and the independent (and/or concurrent) placement of a cantilever force sensor. The findings demonstrate longitudinal contractile and relaxation strains that ranged between 4.8-9.3% in the basal, middle, and apical regions of C57BL/6 mice, and in the mid-ventricular regions of 129/Sv, WT, and MLP mice. Measured forces ranged between 3.1-8.9 mN. The technique's feasibility is also demonstrated in normal mice following afterload, occlusion-reperfusion challenges.Furthermore, the total mid-ventricular forces developed in MLP mice were significantly reduced compared to the WT controls (5.9 ± 0.4 versus 8.9 ± 0.2 mN, p < 0.0001), possibly owing to the fibrotic and stiffer myocardium. No significant strain differences were noted between WT and MLP mice.The possibility of quantifying in vivo force and strain from the normal murine heart is demonstrated with a potential usefulness in the characterisation of transgenic and diseased mice, where regional myocardial function may be significantly altered.
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Affiliation(s)
- M Michaelides
- Department of Mechanical and Manufacturing Engineering, School of Engineering, University of Cyprus, Nicosia, Cyprus. Lecturer, Department of Sport and Exercise Science, UCLan Cyprus, University Avenue 12-14, Pyla 7080, Cyprus
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Mastrototaro G, Liang X, Li X, Carullo P, Piroddi N, Tesi C, Gu Y, Dalton ND, Peterson KL, Poggesi C, Sheikh F, Chen J, Bang ML. Nebulette knockout mice have normal cardiac function, but show Z-line widening and up-regulation of cardiac stress markers. Cardiovasc Res 2015; 107:216-25. [PMID: 25987543 DOI: 10.1093/cvr/cvv156] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2015] [Accepted: 04/26/2015] [Indexed: 02/06/2023] Open
Abstract
AIMS Nebulette is a 109 kDa modular protein localized in the sarcomeric Z-line of the heart. In vitro studies have suggested a role of nebulette in stabilizing the thin filament, and missense mutations in the nebulette gene were recently shown to be causative for dilated cardiomyopathy and endocardial fibroelastosis in human and mice. However, the role of nebulette in vivo has remained elusive. To provide insights into the function of nebulette in vivo, we generated and studied nebulette-deficient (nebl(-) (/-)) mice. METHODS AND RESULTS Nebl(-) (/-) mice were generated by replacement of exon 1 by Cre under the control of the endogenous nebulette promoter, allowing for lineage analysis using the ROSA26 Cre reporter strain. This revealed specific expression of nebulette in the heart, consistent with in situ hybridization results. Nebl(-) (/-) mice exhibited normal cardiac function both under basal conditions and in response to transaortic constriction as assessed by echocardiography and haemodynamic analyses. Furthermore, histological, IF, and western blot analysis showed no cardiac abnormalities in nebl(-) (/-) mice up to 8 months of age. In contrast, transmission electron microscopy showed Z-line widening starting from 5 months of age, suggesting that nebulette is important for the integrity of the Z-line. Furthermore, up-regulation of cardiac stress responsive genes suggests the presence of chronic cardiac stress in nebl(-) (/-) mice. CONCLUSION Nebulette is dispensable for normal cardiac function, although Z-line widening and up-regulation of cardiac stress markers were found in nebl(-) (/-) heart. These results suggest that the nebulette disease causing mutations have dominant gain-of-function effects.
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Affiliation(s)
- Giuseppina Mastrototaro
- Humanitas Clinical and Research Center, Via Manzoni 113, 20089 Rozzano, Milan, Italy University of Milano-Bicocca, Milan, Italy
| | - Xingqun Liang
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0613C, USA
| | - Xiaodong Li
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0613C, USA
| | - Pierluigi Carullo
- Humanitas Clinical and Research Center, Via Manzoni 113, 20089 Rozzano, Milan, Italy Institute of Genetic and Biomedical Research, UOS Milan, National Research Council, Milan, Italy
| | - Nicoletta Piroddi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Chiara Tesi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Yusu Gu
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0613C, USA
| | - Nancy D Dalton
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0613C, USA
| | - Kirk L Peterson
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0613C, USA
| | - Corrado Poggesi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Farah Sheikh
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0613C, USA
| | - Ju Chen
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0613C, USA
| | - Marie-Louise Bang
- Humanitas Clinical and Research Center, Via Manzoni 113, 20089 Rozzano, Milan, Italy Institute of Genetic and Biomedical Research, UOS Milan, National Research Council, Milan, Italy
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Wong AK, Krishnan A, Yao V, Tadych A, Troyanskaya OG. IMP 2.0: a multi-species functional genomics portal for integration, visualization and prediction of protein functions and networks. Nucleic Acids Res 2015; 43:W128-33. [PMID: 25969450 PMCID: PMC4489318 DOI: 10.1093/nar/gkv486] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Accepted: 05/02/2015] [Indexed: 01/08/2023] Open
Abstract
IMP (Integrative Multi-species Prediction), originally released in 2012, is an interactive web server that enables molecular biologists to interpret experimental results and to generate hypotheses in the context of a large cross-organism compendium of functional predictions and networks. The system provides biologists with a framework to analyze their candidate gene sets in the context of functional networks, expanding or refining their sets using functional relationships predicted from integrated high-throughput data. IMP 2.0 integrates updated prior knowledge and data collections from the last three years in the seven supported organisms (Homo sapiens, Mus musculus, Rattus norvegicus, Drosophila melanogaster, Danio rerio, Caenorhabditis elegans, and Saccharomyces cerevisiae) and extends function prediction coverage to include human disease. IMP identifies homologs with conserved functional roles for disease knowledge transfer, allowing biologists to analyze disease contexts and predictions across all organisms. Additionally, IMP 2.0 implements a new flexible platform for experts to generate custom hypotheses about biological processes or diseases, making sophisticated data-driven methods easily accessible to researchers. IMP does not require any registration or installation and is freely available for use at http://imp.princeton.edu.
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Affiliation(s)
- Aaron K Wong
- Department of Computer Science, Princeton University, Princeton, NJ 08540, USA Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540, USA Simons Center for Data Analysis, Simons Foundation, NY 10010, USA
| | - Arjun Krishnan
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540, USA
| | - Victoria Yao
- Department of Computer Science, Princeton University, Princeton, NJ 08540, USA Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540, USA
| | - Alicja Tadych
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540, USA
| | - Olga G Troyanskaya
- Department of Computer Science, Princeton University, Princeton, NJ 08540, USA Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540, USA Simons Center for Data Analysis, Simons Foundation, NY 10010, USA
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Karolczak J, Weis S, Ehler E, Kierdaszuk B, Berdyński M, Zekanowski C, Kamińska AM, Rędowicz MJ. Myosin VI localization and expression in striated muscle pathology. Anat Rec (Hoboken) 2015; 297:1706-13. [PMID: 25125183 DOI: 10.1002/ar.22967] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 02/04/2014] [Indexed: 12/11/2022]
Abstract
Myosin VI (MVI) is a unique unconventional myosin translocating, unlike other myosins, towards the minus end of actin filaments. It is involved in numerous cellular processes such as endocytosis, intracellular trafficking, cell migration, and transcription. In mammalian skeletal muscles it localizes mainly to sarcoplasmic reticulum and is also present within the muscle nuclei and at the neuromuscular junction (Karolczak et al. Histochem Cell Biol 2013; 23:219-228). We have also shown that in denervated rat hindlimb muscle the MVI expression level is significantly increased and its localization is changed, indicating an important role of MVI in striated muscle pathology. Here, we addressed this problem by examining the distribution and expression levels of myosin VI in biopsies of skeletal muscles from patients with different myopathies. We found that, particularly in myopathies associated with fiber atrophy, the amount of MVI was enhanced and its localization in affected fibers was changed. Also, since a mutation within the human MVI gene was shown to be associated with cardiomyopathy, we assessed MVI localization and expression level in cardiac muscle using wild type and MLP(-/-) mice, a dilated cardiomyopathy model. No significant difference in MVI expression level was observed for both types of animals. MVI was found at intercalated discs and also at the sarcoplasmic reticulum. In the knockout mice, it was also present in ring-like structures surrounding the nuclei. The data indicate that in striated muscle MVI could be engaged in sarcoplasmic reticulum maintenance and/or functioning, vesicular transport, signal transmission and possibly in gene transcription.
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Affiliation(s)
- Justyna Karolczak
- Department of Biochemistry, Laboratory of Molecular Basis of Cell Motility, Nencki Institute of Experimental Biology, Warsaw, Poland
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Dwyer J, Pluess M, Iskratsch T, Dos Remedios CG, Ehler E. The formin FHOD1 in cardiomyocytes. Anat Rec (Hoboken) 2015; 297:1560-70. [PMID: 25125170 DOI: 10.1002/ar.22984] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 05/30/2014] [Indexed: 12/20/2022]
Abstract
Members of the formin family are known to be involved in the regulation of the actin cytoskeleton. We have recently identified a muscle specific splice variant of the formin FHOD3 and demonstrated its role in the maintenance of the contractile filaments of cardiomyocytes. Here, we characterize the expression and subcellular localization of FHOD3's closest relative, FHOD1, in the heart. Confocal microscopy shows that FHOD1 is mainly located at the intercalated disc, the special type of cell-cell contact between cardiomyocytes, but also partially associated with the myofibrils. Subcellular targeting of FHOD1 is probably mediated by its N-terminal domain, since expression constructs lacking this domain show aberrant localization in primary cultures of neonatal rat cardiomyocytes. Finally, we show that in contrast to FHOD3, FHOD1 shows increased expression levels in dilated cardiomyopathy, suggesting that the two formins play distinct roles and are differentially regulated in cardiomyocytes.
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Affiliation(s)
- Joseph Dwyer
- Randall Division of Cell and Molecular Biophysics and Cardiovascular Division, British Heart Foundation Centre of Research Excellence, King's College London, SE1 1UL, United Kingdom
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Lun AS, Chen J, Lange S. Probing muscle ankyrin-repeat protein (MARP) structure and function. Anat Rec (Hoboken) 2015; 297:1615-29. [PMID: 25125175 DOI: 10.1002/ar.22968] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 01/02/2014] [Indexed: 12/20/2022]
Abstract
Muscle ankyrin-repeat proteins (MARPs) have been shown to serve diverse functions within cardiac and skeletal muscle cells. Apart from their interactions with sarcomeric proteins like titin or myopalladin that locate them along myofilaments, MARPs are able to shuttle to the nucleus where they act as modulators for a variety of transcription factors. The deregulation of MARPs in many cardiac and skeletal myopathies contributes to their use as biomarkers for these diseases. Many of their functions are attributed to their domain composition. MARPs consist of an N-terminal coiled-coil domain responsible for their dimerization. The C-terminus contains a series of ankyrin repeats, whose best-characterized function is to bind to the N2A region of the giant sarcomeric protein titin. Here we investigate the nature of their dimerization and their interaction with titin more closely. We demonstrate that the coiled-coil domain in all MARPs enables their homo- and hetero-dimerization in antiparallel fashion. Protein complementation experiments indicate further antiparallel binding of the ankyrin repeats to titin's N2A region. Binding of MARP to titin also affects its PKA mediated phosphorylation. We demonstrate further that MARPs themselves are phosphorylated by PKA and PKC, potentially altering their structure or function. These studies elucidate structural relationships within the stretch-responsive MARP/titin complex in cross-striated muscle cells, and may relate to disease relevant posttranslational modifications of MARPs and titin that alter muscle compliance.
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125
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Lyon RC, Zanella F, Omens JH, Sheikh F. Mechanotransduction in cardiac hypertrophy and failure. Circ Res 2015; 116:1462-1476. [PMID: 25858069 PMCID: PMC4394185 DOI: 10.1161/circresaha.116.304937] [Citation(s) in RCA: 237] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 03/13/2015] [Indexed: 01/10/2023]
Abstract
Cardiac muscle cells have an intrinsic ability to sense and respond to mechanical load through a process known as mechanotransduction. In the heart, this process involves the conversion of mechanical stimuli into biochemical events that induce changes in myocardial structure and function. Mechanotransduction and its downstream effects function initially as adaptive responses that serve as compensatory mechanisms during adaptation to the initial load. However, under prolonged and abnormal loading conditions, the remodeling processes can become maladaptive, leading to altered physiological function and the development of pathological cardiac hypertrophy and heart failure. Although the mechanisms underlying mechanotransduction are far from being fully elucidated, human and mouse genetic studies have highlighted various cytoskeletal and sarcolemmal structures in cardiac myocytes as the likely candidates for load transducers, based on their link to signaling molecules and architectural components important in disease pathogenesis. In this review, we summarize recent developments that have uncovered specific protein complexes linked to mechanotransduction and mechanotransmission within the sarcomere, the intercalated disc, and at the sarcolemma. The protein structures acting as mechanotransducers are the first step in the process that drives physiological and pathological cardiac hypertrophy and remodeling, as well as the transition to heart failure, and may provide better insights into mechanisms driving mechanotransduction-based diseases.
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Affiliation(s)
- Robert C. Lyon
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Fabian Zanella
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Jeffrey H. Omens
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
- Department of Bioengineering, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Farah Sheikh
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
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126
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Pluess M, Daeubler G, Dos Remedios CG, Ehler E. Adaptations of cytoarchitecture in human dilated cardiomyopathy. Biophys Rev 2015; 7:25-32. [PMID: 28509975 PMCID: PMC4322184 DOI: 10.1007/s12551-014-0146-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 11/10/2014] [Indexed: 12/30/2022] Open
Abstract
Hypertrophic cardiomyopathy is characterised by a histological phenotype of myocyte disarray, but heart tissue samples from patients with dilated cardiomyopathy (DCM) often look comparatively similar to those from healthy individuals apart from conspicuous regions of fibrosis and necrosis. We have previously investigated subcellular alterations in the cytoarchitecture of mouse models of dilated cardiomyopathy and found that both the organisation and composition of the intercalated disc, i.e. the specialised type of cell-cell contact in the heart, is altered. There is also is a change in the composition of the M-band of the sarcomere due to an expression shift towards the more extensible embryonic heart (EH)-myomesin isoform. Analysis of human samples from the Sydney Human Heart Tissue Bank have revealed similar structural findings and also provided evidence for a dramatic change in overall cardiomyocyte size control, which has also been seen in the mouse. Together these changes in cytoarchitecture probably contribute to the decreased functional output that is seen in DCM.
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Affiliation(s)
- Marlene Pluess
- Randall Division of Cell and Molecular Biophysics and Cardiovascular Division, British Heart Foundation Centre of Research Excellence, King's College London, New Hunt's House, Guy's Campus, London, SE1 1UL, UK
| | - Gregor Daeubler
- Randall Division of Cell and Molecular Biophysics and Cardiovascular Division, British Heart Foundation Centre of Research Excellence, King's College London, New Hunt's House, Guy's Campus, London, SE1 1UL, UK
| | | | - Elisabeth Ehler
- Randall Division of Cell and Molecular Biophysics and Cardiovascular Division, British Heart Foundation Centre of Research Excellence, King's College London, New Hunt's House, Guy's Campus, London, SE1 1UL, UK.
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127
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Caetano-Anollés K, Mishra S, Rodriguez-Zas SL. Synergistic and antagonistic interplay between myostatin gene expression and physical activity levels on gene expression patterns in triceps Brachii muscles of C57/BL6 mice. PLoS One 2015; 10:e0116828. [PMID: 25710176 PMCID: PMC4339580 DOI: 10.1371/journal.pone.0116828] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 12/15/2014] [Indexed: 12/28/2022] Open
Abstract
Levels of myostatin expression and physical activity have both been associated with transcriptome dysregulation and skeletal muscle hypertrophy. The transcriptome of triceps brachii muscles from male C57/BL6 mice corresponding to two genotypes (wild-type and myostatin-reduced) under two conditions (high and low physical activity) was characterized using RNA-Seq. Synergistic and antagonistic interaction and ortholog modes of action of myostatin genotype and activity level on genes and gene pathways in this skeletal muscle were uncovered; 1,836, 238, and 399 genes exhibited significant (FDR-adjusted P-value < 0.005) activity-by-genotype interaction, genotype and activity effects, respectively. The most common differentially expressed profiles were (i) inactive myostatin-reduced relative to active and inactive wild-type, (ii) inactive myostatin-reduced and active wild-type, and (iii) inactive myostatin-reduced and inactive wild-type. Several remarkable genes and gene pathways were identified. The expression profile of nascent polypeptide-associated complex alpha subunit (Naca) supports a synergistic interaction between activity level and myostatin genotype, while Gremlin 2 (Grem2) displayed an antagonistic interaction. Comparison between activity levels revealed expression changes in genes encoding for structural proteins important for muscle function (including troponin, tropomyosin and myoglobin) and for fatty acid metabolism (some linked to diabetes and obesity, DNA-repair, stem cell renewal, and various forms of cancer). Conversely, comparison between genotype groups revealed changes in genes associated with G1-to-S-phase transition of the cell cycle of myoblasts and the expression of Grem2 proteins that modulate the cleavage of the myostatin propeptide. A number of myostatin-feedback regulated gene products that are primarily regulatory were uncovered, including microRNA impacting central functions and Piezo proteins that make cationic current-controlling mechanosensitive ion channels. These important findings extend hypotheses of myostatin and physical activity master regulation of genes and gene pathways, impacting medical practices and therapies associated with muscle atrophy in humans and companion animal species and genome-enabled selection practices applied to food-production animal species.
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Affiliation(s)
- Kelsey Caetano-Anollés
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Sanjibita Mishra
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Khorana Scholars Program, Indo-US Science and Technology Forum, New Delhi, India
- National Institute of Technology, Rourkel, India
| | - Sandra L. Rodriguez-Zas
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Department of Statistics, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- * E-mail:
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Song W, Wang X. The role of TGFβ1 and LRG1 in cardiac remodelling and heart failure. Biophys Rev 2015; 7:91-104. [PMID: 28509980 PMCID: PMC4322186 DOI: 10.1007/s12551-014-0158-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 11/26/2014] [Indexed: 12/12/2022] Open
Abstract
Heart failure is a life-threatening condition that carries a considerable emotional and socio-economic burden. As a result of the global increase in the ageing population, sedentary life-style, increased prevalence of risk factors, and improved survival from cardiovascular events, the incidence of heart failure will continue to rise. Despite the advances in current cardiovascular therapies, many patients are not suitable for or may not benefit from conventional treatments. Thus, more effective therapies are required. Transforming growth factor (TGF) β family of cytokines is involved in heart development and dys-regulated TGFβ signalling is commonly associated with fibrosis, aberrant angiogenesis and accelerated progression into heart failure. Therefore, a potential therapeutic pathway is to modulate TGFβ signalling; however, broad blockage of TGFβ signalling may cause unwanted side effects due to its pivotal role in tissue homeostasis. We found that leucine-rich α-2 glycoprotein 1 (LRG1) promotes blood vessel formation via regulating the context-dependent endothelial TGFβ signalling. This review will focus on the interaction between LRG1 and TGFβ signalling, their involvement in the pathogenesis of heart failure, and the potential for LRG1 to function as a novel therapeutic target.
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Affiliation(s)
- Weihua Song
- Division of Metabolic Medicine, Lee Kong Chian School of Medicine, Nanyang Technological University, Research Techno Plaza, X-Frontiers Block, Level 4, 50 Nan yang Drive, Singapore, 637553, Singapore
| | - Xiaomeng Wang
- Division of Metabolic Medicine, Lee Kong Chian School of Medicine, Nanyang Technological University, Research Techno Plaza, X-Frontiers Block, Level 4, 50 Nan yang Drive, Singapore, 637553, Singapore. .,Division of Cell Biology in Health and Disease, Institute of Molecular and Cell Biology, Singapore Agency for Science, Technology and Research, 61 Biopolis Drive, Proteos, Singapore, 138673, Singapore. .,Department of Cell Biology, Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK.
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129
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Maier J, Sawall S, Kachelrieß M. Assessment of dedicated low-dose cardiac micro-CT reconstruction algorithms using the left ventricular volume of small rodents as a performance measure. Med Phys 2014; 41:051908. [PMID: 24784387 DOI: 10.1118/1.4870983] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Phase-correlated microcomputed tomography (micro-CT) imaging plays an important role in the assessment of mouse models of cardiovascular diseases and the determination of functional parameters as the left ventricular volume. As the current gold standard, the phase-correlated Feldkamp reconstruction (PCF), shows poor performance in case of low dose scans, more sophisticated reconstruction algorithms have been proposed to enable low-dose imaging. In this study, the authors focus on the McKinnon-Bates (MKB) algorithm, the low dose phase-correlated (LDPC) reconstruction, and the high-dimensional total variation minimization reconstruction (HDTV) and investigate their potential to accurately determine the left ventricular volume at different dose levels from 50 to 500 mGy. The results were verified in phantom studies of a five-dimensional (5D) mathematical mouse phantom. METHODS Micro-CT data of eight mice, each administered with an x-ray dose of 500 mGy, were acquired, retrospectively gated for cardiac and respiratory motion and reconstructed using PCF, MKB, LDPC, and HDTV. Dose levels down to 50 mGy were simulated by using only a fraction of the projections. Contrast-to-noise ratio (CNR) was evaluated as a measure of image quality. Left ventricular volume was determined using different segmentation algorithms (Otsu, level sets, region growing). Forward projections of the 5D mouse phantom were performed to simulate a micro-CT scan. The simulated data were processed the same way as the real mouse data sets. RESULTS Compared to the conventional PCF reconstruction, the MKB, LDPC, and HDTV algorithm yield images of increased quality in terms of CNR. While the MKB reconstruction only provides small improvements, a significant increase of the CNR is observed in LDPC and HDTV reconstructions. The phantom studies demonstrate that left ventricular volumes can be determined accurately at 500 mGy. For lower dose levels which were simulated for real mouse data sets, the HDTV algorithm shows the best performance. At 50 mGy, the deviation from the reference obtained at 500 mGy were less than 4%. Also the LDPC algorithm provides reasonable results with deviation less than 10% at 50 mGy while PCF and MKB reconstruction show larger deviations even at higher dose levels. CONCLUSIONS LDPC and HDTV increase CNR and allow for quantitative evaluations even at dose levels as low as 50 mGy. The left ventricular volumes exemplarily illustrate that cardiac parameters can be accurately estimated at lowest dose levels if sophisticated algorithms are used. This allows to reduce dose by a factor of 10 compared to today's gold standard and opens new options for longitudinal studies of the heart.
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Affiliation(s)
- Joscha Maier
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Stefan Sawall
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany and Institute of Medical Physics, University of Erlangen-Nürnberg, 91052 Erlangen, Germany
| | - Marc Kachelrieß
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany and Institute of Medical Physics, University of Erlangen-Nürnberg, 91052 Erlangen, Germany
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130
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Abstract
SIGNIFICANCE Heart failure (HF) is a common end point for many underlying cardiovascular diseases. Down-regulation and desensitization of β-adrenergic receptors (β-AR) caused by G-protein-coupled receptor (GPCR) kinase 2 (GRK2) are prominent features of HF. Recent Advances and Critical Issues: Significant progress has been made to understand the pathological role of GRK2 in the heart both as a GPCR kinase and as a molecule that can exert GPCR-independent effects. Inhibition of cardiac GRK2 has proved to be therapeutic in the failing heart and may offer synergistic and additional benefits to β-blocker therapy. However, the mechanisms of how GRK2 directly contributes to the pathogenesis of HF need further investigation, and additional verification of the mechanistic details are needed before GRK2 inhibition can be used for the treatment of HF. FUTURE DIRECTIONS The newly identified characteristics of GRK2, including the S-nitrosylation of GRK2 and the localization of GRK2 on mitochondria, merit further investigation. They may contribute to it being a pro-death kinase and result in HF under stressed conditions through regulation of intracellular signaling, including cardiac reduction-oxidation (redox) balance. A thorough understanding of the functions of GRK2 in the heart is necessary in order to finalize it as a candidate for drug development.
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Affiliation(s)
- Zheng Maggie Huang
- Department of Pharmacology and Center for Translational Medicine, Temple University School of Medicine , Philadelphia, Pennsylvania
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Hou Y, Crossman DJ, Rajagopal V, Baddeley D, Jayasinghe I, Soeller C. Super-resolution fluorescence imaging to study cardiac biophysics: α-actinin distribution and Z-disk topologies in optically thick cardiac tissue slices. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 115:328-39. [PMID: 25042577 DOI: 10.1016/j.pbiomolbio.2014.07.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Accepted: 07/09/2014] [Indexed: 10/25/2022]
Abstract
A major motivation for the use of super-resolution imaging methods in the investigation of cardiac biophysics has been the insight from biophysical considerations and detailed mathematical modeling that the spatial structure and protein organisation at the scale of nanometres can have enormous implications for calcium signalling in cardiac muscle. We illustrate the use of dSTORM based super-resolution in optically thick (∼10 μm) tissue slices of rat ventricular tissue to visualize proteins at the cardiac Z-disk and compare those images with confocal (diffraction-limited) as well as electron microscopy (EM) data which still provides a benchmark in terms of resolution. α-actinin is an abundant protein target that effectively defines the Z-disk in striated muscle and provides a reference structure for other proteins at the Z-line and the transverse tubules. Using super-resolution imaging α-actinin labelling provides very detailed outlines of the contractile machinery which we have used to study the properties of Z-disks and the distribution of α-actinin itself. We determined the local diameters of the myo-fibrillar and non-myofibrillar space using α-actinin labelling. Comparison between confocal and super-resolution based myofibrillar masks suggested that super-resolution data was able to segment myofibrils accurately while confocal approaches were not always able to distinguish neighbouring myofibrillar bundles which resulted in overestimated diameters. The increased resolution of super-resolution methods provides qualitatively new information to improve our understanding of cardiac biophysics. Nevertheless, conventional diffraction-limited imaging still has an important role to play which we illustrate with correlative confocal and super-resolution data.
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Affiliation(s)
- Yufeng Hou
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - David J Crossman
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Vijay Rajagopal
- Dept. of Electrical and Electronic Engineering, University of Melbourne, Australia
| | - David Baddeley
- Department of Physiology, University of Auckland, Auckland, New Zealand; Department of Cell Biology, Yale University, New Haven, USA
| | | | - Christian Soeller
- Department of Physiology, University of Auckland, Auckland, New Zealand; Biomedical Physics, University of Exeter, UK.
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132
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Levin E, Leibinger M, Andreadaki A, Fischer D. Neuronal expression of muscle LIM protein in postnatal retinae of rodents. PLoS One 2014; 9:e100756. [PMID: 24945278 PMCID: PMC4063954 DOI: 10.1371/journal.pone.0100756] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 05/30/2014] [Indexed: 01/22/2023] Open
Abstract
Muscle LIM protein (MLP) is a member of the cysteine rich protein family and has so far been regarded as a muscle-specific protein that is mainly involved in myogenesis and the organization of cytoskeletal structure in myocytes, respectively. The current study demonstrates for the first time that MLP expression is not restricted to muscle tissue, but is also found in the rat naive central nervous system. Using quantitative PCR, Western blot and immunohistochemical analyses we detected MLP in the postnatal rat retina, specifically in the somas and dendritic arbors of cholinergic amacrine cells (AC) of the inner nuclear layer and the ganglion cell layer (displaced AC). Induction of MLP expression started at embryonic day 20 and peaked between postnatal days 7 and 14. It subsequently decreased again to non-detectable protein levels after postnatal day 28. MLP was identified in the cytoplasm and dendrites but not in the nucleus of AC. Thus, retinal MLP expression correlates with the morphologic and functional development of cholinergic AC, suggesting a potential role of this protein in postnatal maturation and making MLP a suitable marker for these neurons.
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Affiliation(s)
- Evgeny Levin
- Division of Experimental Neurology, Department of Neurology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Marco Leibinger
- Division of Experimental Neurology, Department of Neurology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Anastasia Andreadaki
- Division of Experimental Neurology, Department of Neurology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Dietmar Fischer
- Division of Experimental Neurology, Department of Neurology, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
- * E-mail:
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133
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Human muscle LIM protein dimerizes along the actin cytoskeleton and cross-links actin filaments. Mol Cell Biol 2014; 34:3053-65. [PMID: 24934443 DOI: 10.1128/mcb.00651-14] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The muscle LIM protein (MLP) is a nucleocytoplasmic shuttling protein playing important roles in the regulation of myocyte remodeling and adaptation to hypertrophic stimuli. Missense mutations in human MLP or its ablation in transgenic mice promotes cardiomyopathy and heart failure. The exact function(s) of MLP in the cytoplasmic compartment and the underlying molecular mechanisms remain largely unknown. Here, we provide evidence that MLP autonomously binds to, stabilizes, and bundles actin filaments (AFs) independently of calcium and pH. Using total internal reflection fluorescence microscopy, we have shown how MLP cross-links actin filaments into both unipolar and mixed-polarity bundles. Quantitative analysis of the actin cytoskeleton configuration confirmed that MLP substantially promotes actin bundling in live myoblasts. In addition, bimolecular fluorescence complementation (BiFC) assays revealed MLP self-association. Remarkably, BiFC complexes mostly localize along actin filament-rich structures, such as stress fibers and sarcomeres, supporting a functional link between MLP self-association and actin cross-linking. Finally, we have demonstrated that MLP self-associates through its N-terminal LIM domain, whereas it binds to AFs through its C-terminal LIM domain. Together our data support that MLP contributes to the maintenance of cardiomyocyte cytoarchitecture by a mechanism involving its self-association and actin filament cross-linking.
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134
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Vafiadaki E, Arvanitis DA, Papalouka V, Terzis G, Roumeliotis TI, Spengos K, Garbis SD, Manta P, Kranias EG, Sanoudou D. Muscle lim protein isoform negatively regulates striated muscle actin dynamics and differentiation. FEBS J 2014; 281:3261-79. [PMID: 24860983 DOI: 10.1111/febs.12859] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 05/14/2014] [Accepted: 05/22/2014] [Indexed: 11/28/2022]
Abstract
Muscle lim protein (MLP) has emerged as a critical regulator of striated muscle physiology and pathophysiology. Mutations in cysteine and glycine-rich protein 3 (CSRP3), the gene encoding MLP, have been directly associated with human cardiomyopathies, whereas aberrant expression patterns are reported in human cardiac and skeletal muscle diseases. Increasing evidence suggests that MLP has an important role in both myogenic differentiation and myocyte cytoarchitecture, although the full spectrum of its intracellular roles has not been delineated. We report the discovery of an alternative splice variant of MLP, designated as MLP-b, showing distinct expression in neuromuscular disease and direct roles in actin dynamics and muscle differentiation. This novel isoform originates by alternative splicing of exons 3 and 4. At the protein level, it contains the N-terminus first half LIM domain of MLP and a unique sequence of 22 amino acids. Physiologically, it is expressed during early differentiation, whereas its overexpression reduces C2C12 differentiation and myotube formation. This may be mediated through its inhibition of MLP/cofilin-2-mediated F-actin dynamics. In differentiated striated muscles, MLP-b localizes to the sarcomeres and binds directly to Z-disc components, including α-actinin, T-cap and MLP. The findings of the present study unveil a novel player in muscle physiology and pathophysiology that is implicated in myogenesis as a negative regulator of myotube formation, as well as in differentiated striated muscles as a contributor to sarcomeric integrity.
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Affiliation(s)
- Elizabeth Vafiadaki
- Molecular Biology Division, Biomedical Research Foundation of the Academy of Athens, Greece
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RNA-sequencing analysis reveals new alterations in cardiomyocyte cytoskeletal genes in patients with heart failure. J Transl Med 2014; 94:645-53. [PMID: 24709777 DOI: 10.1038/labinvest.2014.54] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 02/12/2014] [Accepted: 02/26/2014] [Indexed: 12/15/2022] Open
Abstract
Changes in cardiomyocyte cytoskeletal components, a crucial scaffold of cellular structure, have been found in heart failure (HF); however, the altered cytoskeletal network remains to be elucidated. This study investigated a new map of cytoskeleton-linked alterations that further explain the cardiomyocyte morphology and contraction disruption in HF. RNA-Sequencing (RNA-Seq) analysis was performed in 29 human LV tissue samples from ischemic cardiomyopathy (ICM; n=13) and dilated cardiomyopathy (DCM, n=10) patients undergoing cardiac transplantation and six healthy donors (control, CNT) and up to 16 ICM, 13 DCM and 7 CNT tissue samples for qRT-PCR. Gene Ontology analysis of RNA-Seq data demonstrated that cytoskeletal processes are altered in HF. We identified 60 differentially expressed cytoskeleton-related genes in ICM and 58 genes in DCM comparing with CNT, hierarchical clustering determined that shared cytoskeletal genes have a similar behavior in both pathologies. We further investigated MYLK4, RHOU, and ANKRD1 cytoskeletal components. qRT-PCR analysis revealed that MYLK4 was downregulated (-2.2-fold; P<0.05) and ANKRD1 was upregulated (2.3-fold; P<0.01) in ICM patients vs CNT. RHOU mRNA levels showed a statistical trend to decrease (-2.9-fold). In DCM vs CNT, MYLK4 (-4.0-fold; P<0.05) and RHOU (-3.9-fold; P<0.05) were downregulated and ANKRD1 (2.5-fold; P<0.05) was upregulated. Accordingly, MYLK4 and ANKRD1 protein levels were decreased and increased, respectively, in both diseases. Furthermore, ANKRD1 and RHOU mRNA levels were related with LV function (P<0.05). In summary, we have found a new map of changes in the ICM and DCM cardiomyocyte cytoskeleton. ANKRD1 and RHOU mRNA levels were related with LV function which emphasizes their relevance in HF. These new cytoskeletal changes may be responsible for altered contraction and cell architecture disruption in HF patients. Moreover, these results improve our knowledge on the role of cytoskeleton in functional and structural alterations in HF.
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Renger A, Zafiriou MP, Noack C, Pavlova E, Becker A, Sharkova K, Bergmann MW, El-Armouche A, Zimmermann WH, Zelarayán LC. The four and a half LIM-domain 2 controls early cardiac cell commitment and expansion via regulating β-catenin-dependent transcription. Stem Cells 2014; 31:928-40. [PMID: 23341242 PMCID: PMC3744766 DOI: 10.1002/stem.1332] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Accepted: 12/21/2012] [Indexed: 12/13/2022]
Abstract
The multiphasic regulation of the Wnt/β-catenin canonical pathway is essential for cardiogenesis in vivo and in vitro. To achieve tight regulation of the Wnt/β-catenin signaling, tissue- and cell-specific coactivators and repressors need to be recruited. The identification of such factors may help to elucidate mechanisms leading to enhanced cardiac differentiation efficiency in vitro as well as promote regeneration in vivo. Using a yeast-two-hybrid screen, we identified four-and-a-half-LIM-domain 2 (FHL2) as a cardiac-specific β-catenin interaction partner and activator of Wnt/β-catenin-dependent transcription. We analyzed the role of this interaction for early cardiogenesis in an in vitro model by making use of embryoid body cultures from mouse embryonic stem cells (ESCs). In this model, stable FHL2 gain-of-function promoted mesodermal cell formation and cell proliferation while arresting cardiac differentiation in an early cardiogenic mesodermal progenitor state. Mechanistically, FHL2 overexpression enhanced nuclear accumulation of β-catenin and activated Wnt/β-catenin-dependent transcription leading to sustained upregulation of the early cardiogenic gene Igfbp5. In an alternative P19 cell model, transient FHL2 overexpression led to early activation of Wnt/β-catenin-dependent transcription, but not sustained high-level of Igfbp5 expression. This resulted in enhanced cardiogenesis. We propose that early Wnt/β-catenin-dependent transcriptional activation mediated by FHL2 is important for the transition to and expansion of early cardiogenic mesodermal cells. Collectively, our findings offer mechanistic insight into the early cardiogenic code and may be further exploited to enhance cardiac progenitor cell activity in vitro and in vivo.
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Affiliation(s)
- Anke Renger
- Department of Pharmacology and, Heart Research Center Göttingen (HRCG), University Medical Center-Georg-August-University-Göttingen, Göttingen, Germany
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High-throughput phenotypic assessment of cardiac physiology in four commonly used inbred mouse strains. J Comp Physiol B 2014; 184:763-75. [PMID: 24788387 DOI: 10.1007/s00360-014-0830-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 03/25/2014] [Accepted: 04/01/2014] [Indexed: 01/19/2023]
Abstract
Mice with genetic alterations are used in heart research as model systems of human diseases. In the last decade there was a marked increase in the recognition of genetic diversity within inbred mouse strains. Increasing numbers of inbred mouse strains and substrains and analytical variation of cardiac phenotyping methods require reproducible, high-throughput methods to standardize murine cardiovascular physiology. We describe methods for non-invasive, reliable, easy and fast to perform echocardiography and electrocardiography on awake mice. This method can be used for primary screening of the murine cardiovascular system in large-scale analysis. We provide insights into the physiological divergence of C57BL/6N, C57BL/6J, C3HeB/FeJ and 129P2/OlaHsd mouse hearts and define the expected normal values. Our report highlights that compared to the other three strains tested C57BL/6N hearts reveal features of heart failure such as hypertrophy and reduced contractile function. We found several features of the mouse ECG to be under genetic control and obtained several strain-specific differences in cardiac structure and function.
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138
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Bang ML, Gu Y, Dalton ND, Peterson KL, Chien KR, Chen J. The muscle ankyrin repeat proteins CARP, Ankrd2, and DARP are not essential for normal cardiac development and function at basal conditions and in response to pressure overload. PLoS One 2014; 9:e93638. [PMID: 24736439 PMCID: PMC3988038 DOI: 10.1371/journal.pone.0093638] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 03/04/2014] [Indexed: 01/07/2023] Open
Abstract
Ankrd1/CARP, Ankrd2/Arpp, and Ankrd23/DARP belong to a family of stress inducible ankyrin repeat proteins expressed in striated muscle (MARPs). The MARPs are homologous in structure and localized in the nucleus where they negatively regulate gene expression as well as in the sarcomeric I-band, where they are thought to be involved in mechanosensing. Together with their strong induction during cardiac disease and the identification of causative Ankrd1 gene mutations in cardiomyopathy patients, this suggests their important roles in cardiac development, function, and disease. To determine the functional role of MARPs in vivo, we studied knockout (KO) mice of each of the three family members. Single KO mice were viable and had no apparent cardiac phenotype. We therefore hypothesized that the three highly homologous MARP proteins may have redundant functions in the heart and studied double and triple MARP KO mice. Unexpectedly, MARP triple KO mice were viable and had normal cardiac function both at basal levels and in response to mechanical pressure overload induced by transverse aortic constriction as assessed by echocardiography and hemodynamic studies. Thus, CARP, Ankrd2, and DARP are not essential for normal cardiac development and function at basal conditions and in response to mechanical pressure overload.
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Affiliation(s)
- Marie-Louise Bang
- Institute of Genetic and Biomedical Research, UOS Milan, National Research Council and Humanitas Clinical and Research Center, Rozzano (Milan), Italy
- * E-mail: (M-LB); (JC)
| | - Yusu Gu
- Department of Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Nancy D. Dalton
- Department of Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Kirk L. Peterson
- Department of Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Kenneth R. Chien
- Department of Cell and Molecular Biology and Medicine, Karolinska Insititutet, Stockholm, Sweden
- Harvard University, Department of Stem Cell and Regenerative Biology, Cambridge, Massachusetts, United States of America
| | - Ju Chen
- Department of Medicine, University of California San Diego, La Jolla, California, United States of America
- * E-mail: (M-LB); (JC)
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139
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Rosado M, Barber CF, Berciu C, Feldman S, Birren SJ, Nicastro D, Goode BL. Critical roles for multiple formins during cardiac myofibril development and repair. Mol Biol Cell 2014; 25:811-27. [PMID: 24430873 PMCID: PMC3952851 DOI: 10.1091/mbc.e13-08-0443] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 11/13/2013] [Accepted: 01/09/2014] [Indexed: 12/31/2022] Open
Abstract
Cardiac and skeletal muscle function depends on the proper formation of myofibrils, which are tandem arrays of highly organized actomyosin contractile units called sarcomeres. How the architecture of these colossal molecular assemblages is established during development and maintained over the lifetime of an animal is poorly understood. We investigate the potential roles in myofibril formation and repair of formin proteins, which are encoded by 15 different genes in mammals. Using quantitative real-time PCR analysis, we find that 13 formins are differentially expressed in mouse hearts during postnatal development. Seven formins immunolocalize to sarcomeres in diverse patterns, suggesting that they have a variety of functional roles. Using RNA interference silencing, we find that the formins mDia2, DAAM1, FMNL1, and FMNL2 are required nonredundantly for myofibrillogenesis. Knockdown phenotypes include global loss of myofibril organization and defective sarcomeric ultrastructure. Finally, our analysis reveals an unanticipated requirement specifically for FMNL1 and FMNL2 in the repair of damaged myofibrils. Together our data reveal an unexpectedly large number of formins, with diverse localization patterns and nonredundant roles, functioning in myofibril development and maintenance, and provide the first evidence of actin assembly factors being required to repair myofibrils.
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MESH Headings
- Actins/genetics
- Actins/metabolism
- Animals
- Animals, Newborn
- Bridged Bicyclo Compounds, Heterocyclic/pharmacology
- Cell Differentiation
- Formins
- Gene Expression Regulation, Developmental
- Heterocyclic Compounds, 4 or More Rings/pharmacology
- Intracellular Signaling Peptides and Proteins/antagonists & inhibitors
- Intracellular Signaling Peptides and Proteins/genetics
- Intracellular Signaling Peptides and Proteins/metabolism
- Mice
- Mice, Inbred C57BL
- Microfilament Proteins/antagonists & inhibitors
- Microfilament Proteins/genetics
- Microfilament Proteins/metabolism
- Microtubule-Associated Proteins/antagonists & inhibitors
- Microtubule-Associated Proteins/genetics
- Microtubule-Associated Proteins/metabolism
- Muscle Development/genetics
- Myocardium/cytology
- Myocardium/metabolism
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/ultrastructure
- NADPH Dehydrogenase/antagonists & inhibitors
- NADPH Dehydrogenase/genetics
- NADPH Dehydrogenase/metabolism
- Primary Cell Culture
- Protein Isoforms/antagonists & inhibitors
- Protein Isoforms/genetics
- Protein Isoforms/metabolism
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- Sarcomeres/metabolism
- Sarcomeres/ultrastructure
- Thiazolidines/pharmacology
- Wound Healing/genetics
- rho GTP-Binding Proteins/antagonists & inhibitors
- rho GTP-Binding Proteins/genetics
- rho GTP-Binding Proteins/metabolism
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Affiliation(s)
| | | | - Cristina Berciu
- Biology Department and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454
| | - Steven Feldman
- Biology Department and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454
| | - Susan J. Birren
- Biology Department and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454
| | - Daniela Nicastro
- Biology Department and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454
| | - Bruce L. Goode
- Biology Department and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454
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140
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Mattiazzi A, Kranias EG. The role of CaMKII regulation of phospholamban activity in heart disease. Front Pharmacol 2014; 5:5. [PMID: 24550830 PMCID: PMC3913884 DOI: 10.3389/fphar.2014.00005] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 01/07/2014] [Indexed: 01/06/2023] Open
Abstract
Phospholamban (PLN) is a phosphoprotein in cardiac sarcoplasmic reticulum (SR) that is a reversible regulator of the Ca2+-ATPase (SERCA2a) activity and cardiac contractility. Dephosphorylated PLN inhibits SERCA2a and PLN phosphorylation, at either Ser16 by PKA or Thr17 by Ca2+-calmodulin-dependent protein kinase (CaMKII), reverses this inhibition. Through this mechanism, PLN is a key modulator of SR Ca2+ uptake, Ca2+ load, contractility, and relaxation. PLN phosphorylation is also the main determinant of β1-adrenergic responses in the heart. Although phosphorylation of Thr17 by CaMKII contributes to this effect, its role is subordinate to the PKA-dependent increase in cytosolic Ca2+, necessary to activate CaMKII. Furthermore, the effects of PLN and its phosphorylation on cardiac function are subject to additional regulation by its interacting partners, the anti-apoptotic HAX-1 protein and Gm or the anchoring unit of protein phosphatase 1. Regulation of PLN activity by this multimeric complex becomes even more important in pathological conditions, characterized by aberrant Ca2+-cycling. In this scenario, CaMKII-dependent PLN phosphorylation has been associated with protective effects in both acidosis and ischemia/reperfusion. However, the beneficial effects of increasing SR Ca2+ uptake through PLN phosphorylation may be lost or even become deleterious, when these occur in association with alterations in SR Ca2+ leak. Moreover, a major characteristic in human and experimental heart failure (HF) is depressed SR Ca2+ uptake, associated with decreased SERCA2a levels and dephosphorylation of PLN, leading to decreased SR Ca2+ load and impaired contractility. Thus, the strategy of altering SERCA2a and/or PLN levels or activity to restore perturbed SR Ca2+ uptake is a potential therapeutic tool for HF treatment. We will review here the role of CaMKII-dependent phosphorylation of PLN at Thr17 on cardiac function under physiological and pathological conditions.
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Affiliation(s)
- Alicia Mattiazzi
- Facultad de Medicina, Centro de Investigaciones Cardiovasculares, Conicet La Plata-Universidad Nacional de La Plata La Plata, Argentina
| | - Evangelia G Kranias
- Department of Pharmacology and Cell Biophysics, College of Medicine, University of Cincinnati Cincinnati, OH, USA
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141
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Fiedler LR, Maifoshie E, Schneider MD. Mouse models of heart failure: cell signaling and cell survival. Curr Top Dev Biol 2014; 109:171-247. [PMID: 24947238 DOI: 10.1016/b978-0-12-397920-9.00002-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Heart failure is one of the paramount global causes of morbidity and mortality. Despite this pandemic need, the available clinical counter-measures have not altered substantially in recent decades, most notably in the context of pharmacological interventions. Cell death plays a causal role in heart failure, and its inhibition poses a promising approach that has not been thoroughly explored. In previous approaches to target discovery, clinical failures have reflected a deficiency in mechanistic understanding, and in some instances, failure to systematically translate laboratory findings toward the clinic. Here, we review diverse mouse models of heart failure, with an emphasis on those that identify potential targets for pharmacological inhibition of cell death, and on how their translation into effective therapies might be improved in the future.
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Affiliation(s)
- Lorna R Fiedler
- British Heart Foundation Centre of Research Excellence, National Heart and Lung Institute, Imperial College London, London, UK.
| | - Evie Maifoshie
- British Heart Foundation Centre of Research Excellence, National Heart and Lung Institute, Imperial College London, London, UK
| | - Michael D Schneider
- British Heart Foundation Centre of Research Excellence, National Heart and Lung Institute, Imperial College London, London, UK.
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142
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He H, Zhang HL, Li ZX, Liu Y, Liu XL. Expression, SNV identification, linkage disequilibrium, and combined genotype association analysis of the muscle-specific gene CSRP3 in Chinese cattle. Gene 2013; 535:17-23. [PMID: 24279998 DOI: 10.1016/j.gene.2013.11.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 11/04/2013] [Accepted: 11/08/2013] [Indexed: 11/28/2022]
Abstract
The cysteine and glycine-rich protein 3 (CSRP3) plays an important role in the myofiber differentiation. Here, we identified five SNVs in all exon and intron regions of the CSRP3 gene using DNA sequencing, PCR-RFLP and forced-PCR-RFLP methods in 554 cattle. Four of the five SNVs were significantly associated with growth performance and carcass traits of the cattle. In addition, we evaluated haplotype frequency and linkage disequilibrium coefficient of five sequence variants. The result of haplotype analysis demonstrated 28 haplotypes present in Qinchuan and two haplotypes in Chinese Holstein. Only haplotypes 1 and 8 were being shared by two populations, haplotype 14 had the highest haplotype frequency in Qinchuan (17.4%) and haplotype 8 had the highest haplotype frequency in Chinese Holstein (94.4%). Statistical analyses of combined genotypes indicated that some combined genotypes were significantly or highly significantly associated with growth and carcass traits in the Qinchuan cattle population. qPCR analyses also showed that bovine CSRP3 gene was exclusively expressed in longissimus dorsi muscle and heart tissues. The data support the high potential of the CSRP3 as a marker gene for the improvement of growth performance and carcass traits in selection programs.
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Affiliation(s)
- Hua He
- College of Animal Science and Technology, Northwest A&F University, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Yangling, Shaanxi 712100, PR China
| | - Hui-Lin Zhang
- College of Animal Science and Technology, Northwest A&F University, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Yangling, Shaanxi 712100, PR China
| | - Zhi-Xiong Li
- College of Animal Science and Technology, Northwest A&F University, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Yangling, Shaanxi 712100, PR China
| | - Yu Liu
- College of Animal Science and Technology, Northwest A&F University, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Yangling, Shaanxi 712100, PR China
| | - Xiao-Lin Liu
- College of Animal Science and Technology, Northwest A&F University, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Yangling, Shaanxi 712100, PR China.
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143
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Abstract
Control and modulation of electrical signaling is vital to normal physiology, particularly in neurons, cardiac myocytes, and skeletal muscle. The orchestrated activities of variable sets of ion channels and transporters, including voltage-gated ion channels (VGICs), are responsible for initiation, conduction, and termination of the action potential (AP) in excitable cells. Slight changes in VGIC activity can lead to severe pathologies including arrhythmias, epilepsies, and paralyses, while normal excitability depends on the precise tuning of the AP waveform. VGICs are heavily posttranslationally modified, with upward of 30% of the mature channel mass consisting of N- and O-glycans. These glycans are terminated typically by negatively charged sialic acid residues that modulate voltage-dependent channel gating directly. The data indicate that sialic acids alter VGIC activity in isoform-specific manners, dependent in part, on the number/location of channel sialic acids attached to the pore-forming alpha and/or auxiliary subunits that often act through saturating electrostatic mechanisms. Additionally, cell-specific regulation of sialylation can affect VGIC gating distinctly. Thus, channel sialylation is likely regulated through two mechanisms that together contribute to a dynamic spectrum of possible gating motifs: a subunit-specific mechanism and regulated (aberrant) changes in the ability of the cell to glycosylate. Recent studies showed that neuronal and cardiac excitability is modulated through regulated changes in voltage-gated Na(+) channel sialylation, suggesting that both mechanisms of differential VGIC sialylation contribute to electrical signaling in the brain and heart. Together, the data provide insight into an important and novel paradigm involved in the control and modulation of electrical signaling.
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Affiliation(s)
- Andrew R Ednie
- Programs in Cardiovascular Research and Neuroscience, Department of Molecular Pharmacology & Physiology, College of Medicine, University of South Florida, Tampa, Florida, USA
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144
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Abstract
Ca²⁺ plays a crucial role in connecting membrane excitability with contraction in myocardium. The hallmark features of heart failure are mechanical dysfunction and arrhythmias; defective intracellular Ca²⁺ homeostasis is a central cause of contractile dysfunction and arrhythmias in failing myocardium. Defective Ca²⁺ homeostasis in heart failure can result from pathological alteration in the expression and activity of an increasingly understood collection of Ca²⁺ homeostatic and structural proteins, ion channels, and enzymes. This review focuses on the molecular mechanisms of defective Ca²⁺ cycling in heart failure and considers how fundamental understanding of these pathways may translate into novel and innovative therapies.
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Affiliation(s)
- Min Luo
- Division of Cardiovascular Medicine, Department of Internal Medicine, Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
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145
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Gomes AC, Falcão-Pires I, Pires AL, Brás-Silva C, Leite-Moreira AF. Rodent models of heart failure: an updated review. Heart Fail Rev 2013; 18:219-49. [PMID: 22446984 DOI: 10.1007/s10741-012-9305-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Heart failure (HF) is one of the major health and economic burdens worldwide, and its prevalence is continuously increasing. The study of HF requires reliable animal models to study the chronic changes and pharmacologic interventions in myocardial structure and function and to follow its progression toward HF. Indeed, during the past 40 years, basic and translational scientists have used small animal models to understand the pathophysiology of HF and find more efficient ways of preventing and managing patients suffering from congestive HF (CHF). Each species and each animal model has advantages and disadvantages, and the choice of one model over another should take them into account for a good experimental design. The aim of this review is to describe and highlight the advantages and drawbacks of some commonly used HF rodents models, including both non-genetically and genetically engineered models, with a specific subchapter concerning diastolic HF models.
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Affiliation(s)
- A C Gomes
- Department of Physiology and Cardiothoracic Surgery, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319, Porto, Portugal
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146
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Ehler E, Moore-Morris T, Lange S. Isolation and culture of neonatal mouse cardiomyocytes. J Vis Exp 2013. [PMID: 24056408 DOI: 10.3791/50154] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Cultured neonatal cardiomyocytes have long been used to study myofibrillogenesis and myofibrillar functions. Cultured cardiomyocytes allow for easy investigation and manipulation of biochemical pathways, and their effect on the biomechanical properties of spontaneously beating cardiomyocytes. The following 2-day protocol describes the isolation and culture of neonatal mouse cardiomyocytes. We show how to easily dissect hearts from neonates, dissociate the cardiac tissue and enrich cardiomyocytes from the cardiac cell-population. We discuss the usage of different enzyme mixes for cell-dissociation, and their effects on cell-viability. The isolated cardiomyocytes can be subsequently used for a variety of morphological, electrophysiological, biochemical, cell-biological or biomechanical assays. We optimized the protocol for robustness and reproducibility, by using only commercially available solutions and enzyme mixes that show little lot-to-lot variability. We also address common problems associated with the isolation and culture of cardiomyocytes, and offer a variety of options for the optimization of isolation and culture conditions.
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147
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Douglas RM, Bowden K, Pattison J, Peterson AB, Juliano J, Dalton ND, Gu Y, Alvarez E, Imamura T, Peterson KL, Witztum JL, Haddad GG, Li AC. Intermittent hypoxia and hypercapnia induce pulmonary artery atherosclerosis and ventricular dysfunction in low density lipoprotein receptor deficient mice. J Appl Physiol (1985) 2013; 115:1694-704. [PMID: 23990245 DOI: 10.1152/japplphysiol.00442.2013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Patients with obstructive sleep apnea, who experience episodic hypoxia and hypercapnia during sleep, often demonstrate increased inflammation, oxidative stress, and dyslipidemia. We hypothesized that sleep apnea patients would be predisposed to the development of atherosclerosis. To dissect the mechanisms involved, we developed an animal model in mice whereby we expose mice to intermittent hypoxia/hypercapnia (IHH) in normobaric environments. Two- to three-month-old low-density lipoprotein receptor deficient (Ldlr(-/-)) mice were fed a high-fat diet for 8 or 16 wk while being exposed to IHH for either 10 h/day or 24 h/day. Plasma lipid levels, pulmonary artery and aortic atherosclerotic lesions, and cardiac function were then assayed. Surprisingly, atherosclerosis in the aorta of IHH mice was similar compared with controls. However, in IHH mice, atherosclerosis was markedly increased in the trunk and proximal branches of the pulmonary artery of exposed mice; even though plasma cholesterol and triglycerides were lower than in controls. Hemodynamic analysis revealed that right ventricular maximum pressure and isovolumic relaxation constant were significantly increased in IHH exposed mice and left ventricular % fractional shortening was reduced. In conclusion, 1) Intermittent hypoxia/hypercapnia remarkably accelerated atherosclerotic lesions in the pulmonary artery of Ldlr(-/-) mice and 2) increased lesion formation in the pulmonary artery was associated with right and left ventricular dysfunction. These findings raise the possibility that patients with obstructive sleep apnea may be susceptible to atherosclerotic disease in the pulmonary vasculature, an observation that has not been previously recognized.
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Affiliation(s)
- Robert M Douglas
- Department of Pediatrics, University of California, San Diego, La Jolla, California
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148
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Scholten A, Preisinger C, Corradini E, Bourgonje VJ, Hennrich ML, van Veen TAB, Swaminathan PD, Joiner ML, Vos MA, Anderson ME, Heck AJR. Phosphoproteomics study based on in vivo inhibition reveals sites of calmodulin-dependent protein kinase II regulation in the heart. J Am Heart Assoc 2013; 2:e000318. [PMID: 23926118 PMCID: PMC3828808 DOI: 10.1161/jaha.113.000318] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
BACKGROUND The multifunctional Ca(2+)- and calmodulin-dependent protein kinase II (CaMKII) is a crucial mediator of cardiac physiology and pathology. Increased expression and activation of CaMKII has been linked to elevated risk for arrhythmic events and is a hallmark of human heart failure. A useful approach to determining CaMKII's role therein is large-scale analysis of phosphorylation events by mass spectrometry. However, current large-scale phosphoproteomics approaches have proved inadequate for high-fidelity identification of kinase-specific roles. The purpose of this study was to develop a phosphoproteomics approach to specifically identify CaMKII's downstream effects in cardiac tissue. METHODS AND RESULTS To identify putative downstream CaMKII targets in cardiac tissue, animals with myocardial-delimited expression of the specific peptide inhibitor of CaMKII (AC3-I) or an inactive control (AC3-C) were compared using quantitative phosphoproteomics. The hearts were isolated after isoproterenol injection to induce CaMKII activation downstream of β-adrenergic receptor agonist stimulation. Enriched phosphopeptides from AC3-I and AC3-C mice were differentially quantified using stable isotope dimethyl labeling, strong cation exchange chromatography and high-resolution LC-MS/MS. Phosphorylation levels of several hundred sites could be profiled, including 39 phosphoproteins noticeably affected by AC3-I-mediated CaMKII inhibition. CONCLUSIONS Our data set included known CaMKII substrates, as well as several new candidate proteins involved in functions not previously implicated in CaMKII signaling.
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Affiliation(s)
- Arjen Scholten
- Biomolecular Mass Spectrometry & Proteomics, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
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149
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Straubinger J, Ruth P, Lukowski R. Cardiac cGMP/cGMP-dependent protein kinase I signalling requires cysteine-rich LIM-only protein 4 (CRP4) to oppose angiotensin II induced hypertrophy and fibrosis. BMC Pharmacol Toxicol 2013. [PMCID: PMC3765539 DOI: 10.1186/2050-6511-14-s1-p68] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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150
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Sequeira V, Nijenkamp LLAM, Regan JA, van der Velden J. The physiological role of cardiac cytoskeleton and its alterations in heart failure. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:700-22. [PMID: 23860255 DOI: 10.1016/j.bbamem.2013.07.011] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 07/01/2013] [Accepted: 07/08/2013] [Indexed: 12/11/2022]
Abstract
Cardiac muscle cells are equipped with specialized biochemical machineries for the rapid generation of force and movement central to the work generated by the heart. During each heart beat cardiac muscle cells perceive and experience changes in length and load, which reflect one of the fundamental principles of physiology known as the Frank-Starling law of the heart. Cardiac muscle cells are unique mechanical stretch sensors that allow the heart to increase cardiac output, and adjust it to new physiological and pathological situations. In the present review we discuss the mechano-sensory role of the cytoskeletal proteins with respect to their tight interaction with the sarcolemma and extracellular matrix. The role of contractile thick and thin filament proteins, the elastic protein titin, and their anchorage at the Z-disc and M-band, with associated proteins are reviewed in physiologic and pathologic conditions leading to heart failure. This article is part of a Special Issue entitled: Reciprocal influences between cell cytoskeleton and membrane channels, receptors and transporters. Guest Editor: Jean Claude Hervé
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Affiliation(s)
- Vasco Sequeira
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands
| | - Louise L A M Nijenkamp
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands
| | - Jessica A Regan
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands; Department of Physiology, Molecular Cardiovascular Research Program, Sarver Heart Center, University of Arizona, Tucson, AZ 85724, USA
| | - Jolanda van der Velden
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands; ICIN-Netherlands Heart Institute, The Netherlands.
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